I have successfully been able to sort the first sheet in my Google spreadsheet onOpen, but I'd like to sort all 4 spreadsheets onOpen and I can't make this work. I've tried quite a few variations in Script Editor, here's my latest:

function onOpen(){
  
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  
  // Sorts the first sheet by the first column, ascending

  var sheet = ss.getSheets()[0];

  var tableRange = sheet.getRange("A3:L999"); // What to sort.

  tableRange.sort({column: 1, ascending: true});


  // Sorts the second sheet by the first column, ascending

  var sheet1 = ss.getSheets()[1];

  var tableRange1 = sheet1.getDataRange("A3:AC999"); // What to sort.

  tableRange1.sort({column: 1, ascending: true});

 
  // Sorts the third sheet by the first column, ascending

  var sheet2 = ss.getSheets()[2];

  var tableRange2 = sheet2.getDataRange("A3:N999"); // What to sort.
  tableRange2.sort({column: 1, ascending: true});
  
  // Sorts the fourth sheet by the first column, ascending

  var sheet3 = ss.getSheets()[3];

  var tableRange3 = sheet3.getDataRange("A3:AC999"); // What to sort.

  tableRange3.sort({column: 1, ascending: true});

  
}